As is well known to those skilled in the art, hydrocarbons may be converted to hydrocarbon derivatives containing functional groups (typified by halogen groups); and these may serve as a starting point for the preparation of further derivatives.
Terminally substituted alkanes (especially those with 8-18 carbons) derived from n-paraffins are valuable chemical intermediates in the production of fatty acids, amines, alcohols, esters, and sulfonates for use as detergents, fabric softeners, lubricant additives, plasticizers, etc. (F. Asinger, Paraffins: Chemistry and Technology, transl. B. J. Hazzard, Pergamon Press, Oxford, 1968, pp. 735-6). By contrast, secondary substituted paraffins derived from these same paraffins generally decompose to form olefins or are unreactive when attempts are made to transform them into alcohols, sulfonates, etc. (Asinger, p. 736; H. Krauch and W. Kunz, Organic Name Reactions, John Wiley, New York, 1964, p. 444; Jack Hine, Physical Organic Chemistry, McGraw-Hill, New York, 1962, Chapt. 6).
The treatment of n-paraffins, under a variety of reaction conditions to introduce, e.g., chlorine, always gives rise to a mixture of 1-chloroalkanes and secondary chloroalkanes. Although there are physical methods (U.S. Pat. No. 3,426,086) for separating the two classes of compounds from one another, and chemical means of separation are feasible utilizing the different orders of reactivity for these compounds (for example, see Chem. Abstr. 62 11671, 1965; D. J. Hurley et al., I. & E.C. Prod. Res. & Devel. 4 44, 1965), no attempts have been made to isolate the 1-chloroalkanes from such chlorination mixtures for use as chemical intermediates because the 1-chloroisomer is formed in very low selectivities. For example, chlorination of n-dodecane using a variety of chlorinating agents and reaction conditions gives only 11-13 percent selectivity of the monochloro product to 1-chlorododecane (G. A. Russell article in Free Radicals, Vol. 1, J. K. Kochi, ed., John Wiley, New York, 1973).
The effect of solvents in directing chlorination to a particular position in an alkane (i.e., affecting the relative reactivities of primary, secondary, and tertiary H's in the molecule has been extensively reviewed [F. asinger, Paraffins; G. A. Russell article; J. P. Soumillion, Indust. Chim. Belge, 35 1071, 1970; and B. Fell and Li-Hoan Kung, Chem. Ber. 98 2871, 1965[). No solvent mentioned in the literature to date has been found to increase the selectivity of chlorination to the terminal position of an n-paraffin (i.e., increase the reactivity of a primary H vs. a secondary H). However, aromatic solvents and other special solvents containing electron-donating groups (sulfides, amines, etc.) have been shown to drastically decrease the amount of 1-chloroalkane formed. The only chlorinated hydrocarbons investigated in the literature are CCl.sub.4 and trichloroethylene. These were stated (see G. A. Russell) to have no effect on the position of chlorination in a paraffin. Soumillion states that CCl.sub.4 is "inert" as far as affecting position of chlorination, and Asinger (p. 761) even states that CCl.sub.4 "has not the slightest effect on the relative reaction velocities of the various types of hydrogen atoms in paraffinic hydrocarbons".
It is an object of this invention to provide a novel process for selective conversion of hydrocarbons. Other objects will be apparent to those skilled in the art.